Nickelodeon's top-ranked series "Clarissa Explains It All" may move to primetime broadcast TV via a pilot deal with CBS.

Viacom, which both owns Nickelodeon and produces "Clarissa Explains It All," plans to use the final episodes on Nickelodeon to promote the CBS project, if the broadcast network goes ahead with the project.

"In fact, we're working with (executive producer Mitchell Kriegman) and Nickelodeon to develop a story line transition to the new show as we complete the last season of the 65 cable episodes," said Viacom Television West Coast president Perry Simon.

And, Nickelodeon may continue to air early episodes of "Clarissa" -- which debuted on Nickelodeon in March 1991 -- after CBS picks up the project.

The broadcast version, "Clarissa," also will be written and executive produced by creator Kriegman. It will continue to star Melissa Joan Hart as a small-town girl who has moved to New York City, and will continue to feature live-action, computer animation and special effects.

Simon said the project may become the model for nurturing Viacom-produced programming on the Viacom network with a view toward eventual broadcast network telecasts.

"While we have to be careful not to look at Nickelodeon as a laboratory, because that's not in their best interests, what this does illustrate is a great example of (Viacom Television) working with a Viacom network to build program assets and can be the model for future efforts," Simon said.